diff --git a/packages/shared/forks/ReactFeatureFlags.www-dynamic.js b/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
index b7e987cbd5..fcda77c24b 100644
--- a/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
+++ b/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
@@ -18,6 +18,8 @@ export const enableComponentStackLocations = __VARIANT__;
 export const disableModulePatternComponents = __VARIANT__;
 export const disableInputAttributeSyncing = __VARIANT__;
 export const enableFilterEmptyStringAttributesDOM = __VARIANT__;
+export const enableModernEventSystem = __VARIANT__;
+export const enableLegacyFBSupport = __VARIANT__;
 
 // These are already tested in both modes using the build type dimension,
 // so we don't need to use __VARIANT__ to get extra coverage.
@@ -29,4 +31,3 @@ export const replayFailedUnitOfWorkWithInvokeGuardedCallback = __DEV__;
 // to __VARIANT__.
 export const enableTrustedTypesIntegration = false;
 export const disableSchedulerTimeoutBasedOnReactExpirationTime = false;
-export const enableModernEventSystem = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.www.js b/packages/shared/forks/ReactFeatureFlags.www.js
index 47e006820e..982bce828c 100644
--- a/packages/shared/forks/ReactFeatureFlags.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.www.js
@@ -25,6 +25,7 @@ export const {
   replayFailedUnitOfWorkWithInvokeGuardedCallback,
   enableModernEventSystem,
   enableFilterEmptyStringAttributesDOM,
+  enableLegacyFBSupport,
 } = dynamicFeatureFlags;
 
 // On WWW, __EXPERIMENTAL__ is used for a new modern build.
@@ -69,8 +70,6 @@ export const disableTextareaChildren = __EXPERIMENTAL__;
 
 export const warnUnstableRenderSubtreeIntoContainer = false;
 
-export const enableLegacyFBSupport = !__EXPERIMENTAL__;
-
 // Internal-only attempt to debug a React Native issue. See D20130868.
 export const throwEarlyForMysteriousError = false;